If there really is a random magnetic field in the LP, it will manifest as noise as the magnetic field is moved past the MC cartridge, much like tape hiss as tape moves past a tape head.
However it will be at a much lower level! So if y'all are hearing a reduced background noise after treatment, I would give the magnetic field idea some credence.
The only problem is, static charges will be interpreted by the cartridges as random changes in voltage (IOW, noise) as well! I would expect wood and plastic body cartridges to be more susceptible... Interesting topic. I don't have any sort of instrumentation that I would deem sensitive enough to sort any of this out, so for me it remains an intellectual challenge; apparently one that is audible. Sheesh.
However it will be at a much lower level! So if y'all are hearing a reduced background noise after treatment, I would give the magnetic field idea some credence.
The only problem is, static charges will be interpreted by the cartridges as random changes in voltage (IOW, noise) as well! I would expect wood and plastic body cartridges to be more susceptible... Interesting topic. I don't have any sort of instrumentation that I would deem sensitive enough to sort any of this out, so for me it remains an intellectual challenge; apparently one that is audible. Sheesh.